Our objective to determine the mode of action of the hamster pancreas carcinogen N-nitrosobis(2-oxopropyl)amine (BOP) is being approached by examination of (1) the metabolism of BOP in vivo and in vitro, particularly to see if N-nitrosomethyl(2-oxopropyl)amine (MOP) is being formed and (2) the response of the target (pancreas) and non-target tissues (principally, liver and salivary gland) to BOP action in terms of DNA alkylation and repair of the DNA damage which ensues from the alkylation.